scholarly journals Investigations on the effect of target angle on the stagnation layer of colliding laser produced plasmas of aluminum and silicon

2021 ◽  
Vol 28 (12) ◽  
pp. 123515
Author(s):  
Haider M. Al-Juboori ◽  
Nadeem Ahmed Malik ◽  
Tom McCormack
Keyword(s):  
Target Angle

scholarly journals Accuracy of Rod Contouring to Desired Angles With and Without a Template: Implications for Achieving Desired Spinal Alignment and Outcomes

2021 ◽  
pp. 219256822199837
Author(s):  
Juan Pablo Sardi ◽  
Christopher P. Ames ◽  
Skye Coffey ◽  
Christopher Good ◽  
Benny Dahl ◽  
...  
Keyword(s):  
Patient Outcomes ◽  
Study Design ◽  
Preoperative Planning ◽  
Biomechanical Study ◽  
Spinal Alignment ◽  
Target Angle ◽  
Proximal Junctional Failure ◽  
Bend Angles

Study Design: Biomechanical Study. Objective: The search for optimal spinal alignment has led to the development of sophisticated formulas and software for preoperative planning. However, preoperative plans are not always appropriately executed since rod contouring during surgery is often subjective and estimated by the surgeon. We aimed to assess whether rods contoured to specific angles with a French rod bender using a template guide will be more accurate than rods contoured without a template. Methods: Ten experienced spine surgeons were requested to contour two 125 × 5.5 mm Ti64 rods to 40°, 60° and 80° without templates and then 2 more rods using 2D metallic templates with the same angles. Rod angles were then measured for accuracy and compared. Results: Average angles for rods bent without a template to 40°, 60° and 80° were 60.2°, 78.9° and 97.5°, respectively. Without a template, rods were overbent by a mean of 18.9°. When using templates of 40°, 60° and 80°, mean bend angles were 41.5°, 59.1° and 78.7°, respectively, with an average underbend of 0.2°. Differences between the template and non-template groups for each target angle were all significant (p < 0.001). Conclusions: Without the template, surgeons tend to overbend rods compared to the desired angle, while surgeons improved markedly with a template guide. This tendency to overbend could have significant impact on patient outcomes and risk of proximal junctional failure and warrants further research to better enable surgeons to more accurately execute preoperative alignment plans.

The Effect of Achieving Immediate Target Angle on Success of Strabismus Surgery in Children

2015 ◽  
Vol 160 (5) ◽  
pp. 913-918 ◽  
Author(s):  
Paulita Pamela Astudillo ◽  
Melissa Cotesta ◽  
Jennifer Schofield ◽  
Stephen Kraft ◽  
Kamiar Mireskandari
Keyword(s):  
Strabismus Surgery ◽  
Target Angle

Getting Your Perforations in a Line Can Mean More-Productive Fracturing

2021 ◽  
Vol 73 (07) ◽  
pp. 18-21
Author(s):  
Stephen Rassenfoss
Keyword(s):  
Hydraulic Fracturing ◽  
Flow Rate ◽  
Test Results ◽  
Choked Flow ◽  
Target Angle ◽  
High Side ◽  
Treat All ◽  
Estimated Ultimate Recovery

Want more production from a shale well? Consider lining up the perforations. A handful of speakers at the recent SPE Hydraulic Fracturing Technology Conference talked about improved fracturing results with oriented perforating—shooting the holes at the same place in the casing, often the top. This breaks from designs that arranged the holes in a helical pattern with each charge angled 60° from the previous one. “We did see indications we are getting better production from oriented perforating,” said Blake Horton, senior completions engineer for Ovintiv (SPE 204177). Production gains were also reported by ConocoPhillips which compared production from similar wells with and without oriented perforating. The analysis was designed to filter out differences in the geology, drilling, and completions. It concluded the value of the added production far exceeded the $20,000-per-well cost of installing the assembly, including a weight bar to tilt the perforating guns into position. “That’s less than the undiscounted value of 400 barrels of oil. An internal study indicated that ConocoPhillips improved estimated ultimate recovery (EUR) by a minimum of 5% when using high-side-oriented perforating,” said Dave Cramer, senior engineering fellow at ConocoPhillips and an early advocate for the method. “For an initial choked flow rate of 1,000 B/D, the payout on investment is 10 days or less,” he said. Ovintiv declined to provide a number, but Horton said ConocoPhillips’ estimate is within Ovintiv’s range based on similar comparisons of wells with and without oriented perforating. That number is at the low end of the estimates offered in discussions about oriented perforating performance at the conference. Higher estimates are questioned by those who doubt the test results can be sustained when the method is scaled up. What was certain is the number of users is rising and includes names such as Shell and Chevron. “We found that oriented perforating definitely helps to treat all the clusters,” said Jon Snyder, a staff completion engineer for ConocoPhillips who presented the paper, adding, “by oriented perforating we mean that when we are perforating, we aim for the high side of the wellbore” (SPE 204203). When Horton polled the audience at a recent talk, more than half of the respondents said they were using gun systems designed to orient the perforating charges at a target angle. “A year from now, few people will not be doing oriented perforating; the advantages of it are clear,” Cramer said. He has been promoting the idea within the company for years with mixed acceptance.

Effects of stimulation frequencies and patterns on performance of repetitive, nonisometric tasks

2002 ◽  
Vol 92 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Maikutlo B. Kebaetse ◽  
Amanda E. Turner ◽  
Stuart A. Binder-Macleod
Keyword(s):  
Isometric Force ◽  
Knee Extension ◽  
Variable Frequency ◽  
Constant Frequency ◽  
Human Knee ◽  
Target Angle ◽  
Single Pattern ◽  
The Subject ◽  
Stimulation Pattern ◽  
Quadriceps Femoris Muscles

The purpose of this paper was to determine the effects of stimulation pattern and frequency on repetitive human knee movements. Quadriceps femoris muscles were stimulated against a load equal to 10% of each subject's maximum voluntary isometric force. The main variable of interest was the number of repetitions in which the leg reached a target angle of 40° of knee extension. Sixteen different trains were tested, including 1) six constant-frequency trains with frequencies ranging from 9 to 100 Hz, 2) five variable-frequency trains with an initial 5-ms triplet and mean frequencies ranging from 11 to 35 Hz, and 3) five doublet-frequency trains, which used doublets (2 pulses with a 5-ms interpulse interval) to replace single pulses, with mean frequencies of 17–57 Hz. Testing was stopped when the subject failed to reach the target angle for three consecutive activations. Results showed that no single pattern was best for all subjects. The 33- and 100-Hz constant-frequency trains, 35-Hz variable-frequency trains, and 27- and 36-Hz doublet frequency trains each met the target the most times for some subjects. The results showed that, under our testing conditions, higher frequency trains were better suited for producing repetitive knee movements than lower frequency trains.

scholarly journals Synthesis of Line of Sight Angle Coordinate Filter on the Basis of Interactive Multi-Model Evaluation Algorithm

2021 ◽  
Vol 20 (6) ◽  
pp. 1333-1367
Author(s):  
Dang Trung ◽  
Nguyen Tuan ◽  
Nguyen Bang ◽  
Tran Tuyen
Keyword(s):  
Evaluation Process ◽  
Line Of Sight ◽  
Detection Delay ◽  
Target Angle ◽  
Phase Coordinates ◽  
Acceleration Model ◽  
Evaluation Algorithm ◽  
Cv Model ◽  
Different Levels

On the basis of the tracking multi-loop target angle coordinate system, the article has selected and proposed a interactive multi-model adaptive filter algorithm to improve the quality of the target phase coordinate filter. In which, the 3 models selected to design the line of sight angle coordinate filter; Constant velocity (CV) model, Singer model and constant acceleration model, characterizing 3 different levels of maneuverability of the target. As a result, the evaluation quality of the target phase coordinates is improved because the evaluation process has redistribution of the probabilities of each model to suit the actual maneuvering of the target. The structure of the filters is simple, the evaluation error is small and the maneuvering detection delay is significantly reduced. The results are verified through simulation, ensuring that in all cases the target is maneuvering with different intensity and frequency, the line of sight angle coordinate filter always accurately determines the target angle coordinates.

Effect of Load, Angle, and Contraction Type on Clinically Assessed Knee Joint Position Sense

2021 ◽  
pp. 1-6
Author(s):  
Adam L. Haggerty ◽  
Janet E. Simon ◽  
Dustin R. Grooms ◽  
Jeffrey A. Russell
Keyword(s):  
Body Position ◽  
Eccentric Contraction ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Active Joint ◽  
Concentric Contraction ◽  
Target Angle ◽  
Significant Difference ◽  
Contraction Type

Context: Proprioception is an individual’s awareness of body position in 3-dimensional space. How proprioceptive acuity changes under varying conditions such as joint position, load, and concentric or eccentric contraction type is not well understood. In addition, a limitation of the variety of techniques to assess proprioception is the lack of clinically feasible methods to capture proprioceptive acuity. The purpose of this study was to implement a readily available instrument, a smartphone, in the clinical evaluation of knee active joint position sense and to determine how joint angle, joint loading, and quadriceps contraction type affect an individual’s active joint position sense. Design: Cross-over study. Methods: Twenty healthy, physically active university participants (10 women and 10 men: 21.4 [2.0] y; 1.73 [0.1] m; 70.9 [14.3] kg) were recruited. Individuals were included if they had no neurological disorder, no prior knee surgery, and no recent knee injury. The participants were given a verbal instruction to locate a target angle and then were tasked with reproducing the target angle without visual or verbal cues. An accelerometer application on a smartphone was used to assess the angle to the nearest tenth of a degree. Three variables, each with 2 levels, were analyzed in this study: load (weighted and unweighted), contraction type (eccentric and concentric), and joint position (20° and 70°). A repeated-measures analysis of variance was conducted to assess the within-subjects factors of load, contraction, and position. Results: A significant difference of 0.50° (0.19°) of greater error with eccentric versus concentric contraction (P = .02) type was identified. In addition, a significant interaction was found for contraction × position, with a mean increase in error of 0.98° (0.33°) at the 20° position when contracting eccentrically (P = .03). Conclusions: Contraction type, specifically eccentric contraction at 20°, showed significantly greater error than concentric contraction. This suggests that, during eccentric contractions of the quadriceps, there may be decreased proprioceptive sensitivity compared with concentric contractions.

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